The present invention relates to television (TV) systems, and in particular, to a TV graphical user interface (GUI) having scroll bars and a direct access bar in a graphical channel changer
The growing availability of TV broadcast and interactive services creates a need for a new type of a TV control system that would facilitate user access to options offered by TV program providers. For example, direct broadcast satellite services require users to make their selection among about a thousand TV channels with various TV programs and services. Direct television satellite broadcasting is provided via direct broadcast satellites at an uplink frequency of 17.3 to 17.9 GHz and a downlink frequency of 12.2 to 12.7 Ghz.
A digital satellite television system for direct television broadcasting includes a transmitter for transmitting television signals including video and audio components to a satellite. The satellite retransmits the received television signals to an outdoor antenna assembly that includes a dish-like antenna and a block converter. The dish-like antenna directs the received television signals to the block converter that converts he frequencies of the received television signals to respective lower frequencies.
The television signals produced by the block converter are connected via a coaxial cable to an indoor satellite receiver coupled to a TV set. The satellite receiver tunes, demodulates and otherwise processes the received television signals to provide video and audio signals with a NTSC, PAL or SECAM format suitable for processing by the TV set that produces an image on a display screen in response to the video signals, and an audible response by means of speakers in response to the audio signals.
Within the transmitter, analog video and audio signals are converted to respective digital signals compressed according to the Motion Picture Expert Group (MPEG) encoding standard. The resultant digital signals are represented by a stream of packets including error correction data. The type of packets is identified by a header code. Packets corresponding to control data may also be added to the packet stream.
In the MPEG standard, the video information may be transmitted in the form of a luminance (Y) component and two color difference (U and V) components.; For example, the first color difference component may represent the difference between the red image information and the luminance image information (Rxe2x88x92Y), and the second color difference component may represent the difference between the blue image information and the luminance image information (Bxe2x88x92Y). In addition, the color information is compressed because the two color difference components correspond to more than one picture element. The use of color difference components and the sharing of the color difference components between picture elements reduces the transmission bandwidth.
The digital information resulting from the compression and error correction encoding is modulated on a carrier using Quaternary Phase Shift Keying (QPSK) modulation and transmitted to a satellite for retransmission.
The satellite receiver comprises a tuner for selecting the appropriate carrier signal retransmitted by the satellite and for converting the frequency of the selected carrier to an intermediate frequency (IF) signal. A QPSK demodulator demodulates the IF signal and supplies it to an error-correcting decoder to correct demodulated packets representing video and audio information. An MPEG decoder decodes and decompresses video and audio packets to form digital video and audio signals supplied to a TV set. A TV set-top box serves to deliver compressed digital video and audio signals in real time usable form to one or more TV sets.
As discussed above, the digital satellite television system may provide about 1,000 TV channels with various TV programs and services. To facilitate user access to available TV programs and services, a graphical menu, such as a TV program guide, may be displayed on a TV screen. Due to xe2x80x9coverscanxe2x80x9d conditions, a television receiver may produce a raster so that a picture on its screen may not be entirely in the view of the user. To prevent data loss caused by the overscan conditions, TV broadcast systems display images inside a safe area located within approximately a 10% border all around the edge of the screen.
In conventional TV systems, graphics data are generated so as to position graphical objects, such as control buttons, inside the safe area to ensure that they appear on the screen even under the worst overscan conditions. However, such an arrangement results in reducing the size of graphical objects. This makes them difficult to find and use.
Moreover, when there are; no overscan conditions or overscan is less than in the worst case, a blank band leaves between the safe area and the edge of the screen.
Therefore, it would be desirable to keep graphical objects large and to fully utilize the screen area independently of overscan.
Further, it may be difficult to find a required TV channel among 1,000 channels provided by satellite TV, when the user does not know the number of the required channel. It would be desirable to provide a direct access system that would enable the user to have access to a group of channels that contains the required channel.
Accordingly, one advantage of the present invention is in providing a TV graphical user interface (GUI) having a direct access system that enables a user to have access to a group of channels that contains a required channel when the user does not know the number of the required channel.
Another advantage of the present invention is in providing a TV GUI having large graphical control objects.
A further advantage of the present invention is in providing a GUI on a TV screen that fully utilizes the screen area independently of overscan.
The above and other advantages of the invention are achieved, at least in part, by providing a TV system that comprises a CPU, and a TV monitor controlled by the CPU for displaying a GUI having channel objects for identifying TV channels.
In accordance with one aspect of the invention, a direct access object is provided for indicating a list of TV channels. The channel objects identify a selected group of TV channels when a user directs a pointing device at an area of the direct access object that represents the selected group of TV channels.
The direct access object may comprise a direct access bar having a graduated scale representing the entire sequence of TV channels in the domain of choice. A TV channel may be represented by a region on the direct access bar. The sequence order may be numerical by channel number or alphabetical by channel name. When the user directs the pointing device at a region of the direct access bar that corresponds to a required TV channel, and the user presses select, then the channel objects identify the required TV channel and the TV channels having numbers immediately before and after the number of the required TV channel. When the pointing device is held in the direction of the direct access object, the object may change its color.
For example, the channel objects may identify numbers and logos of the TV channels. When the user and directs the pointing device at a channel object identifying a selected TV channel, and presses select, then an RF tuner switches to the frequency of the selected TV channel.
In accordance with another aspect of the invention, the GUI displayed on a TV screen has a control object for changing TV channels identified by the channel objects. The control object is arranged so as to overlap the edge of a safe area provided on the screen to accommodate a picture to overscan conditions. For example, the control object may extend to the edge of the screen.
The control object may comprise a control bar extended between opposite edges of the screen. The control bar contains an up object for scanning through a list of the TV channels in a first direction, and a down object for scanning through the list of the TV channels in a second direction opposite to the first direction. The channel objects identify the TV channels being scanned.
A border between the up and down objects may move when the TV channels are being scanned. Also, the sizes of the up and down objects may change.
The control bar may comprise an indicator showing a position of a current TV channel being scanned, relative to the list of TV channels. The indicator may be arranged between the up and down objects.
In accordance with a method of the present invention, the following steps are carried out to identify a selected group of TV channels:
checking a position of a cursor moved by a pointing device,
detecting when the cursor is positioned over the direct access object,
determining a coordinate of the cursor when the pointing device is clicked, that is, the select function is pressed,
calculating a position of the cursor relative to the direct access object,
determining a nearest TV channel corresponding to the relative position, and
redrawing the channel objects to identify the selected group composed of the nearest TV channel and the TV channels having numbers before and after the number of the nearest TV channel.